Electronic equipment racks commonly consist of rectangular or box-shaped housings or rack structures. Electronic equipment is commonly mountable in such racks so that the various electronic components are aligned vertically one on top of the other in the rack. Often, multiple racks are oriented side-by-side, with each rack containing numerous electronic components and having substantial quantities of associated component wiring located both within and outside of the area occupied by the racks.
Power distribution units have long been utilized to supply power to the equipment in such racks. Power distribution units have also been designed to allow a user to remotely monitor and control the power distribution unit or devices attached to the power distribution unit. Examples of such power distribution units can be found in U.S. Pat. Nos. 5,506,573, 5,949,947, and 6,711,613.
One particularly common such power distribution unit consists of an elongated box housing that has one or more power inputs penetrating the housing and a number of power outputs extending along the longitudinal face of the unit. This power distribution unit is designed to mount vertically adjacent or secured to the external rear side of a rack. In this fashion, the power supplied to the unit is then distributed through horizontally extending power outputs to the, typically, horizontally co-aligned electronic components mounted in the rack. An example of such a prior power distribution unit is sold under the trademark POWER TOWER by Server Technology, Inc., of Reno, Nev.
As previously stated, each power distribution unit typically contains a number of power outputs and at least one power input. The power distribution units may also contain other electronic components, such as fuses and monitoring devices.
Some prior art power distribution units are protected by fuses or other devices to protect the power distribution unit and attached electronic devices against current fluctuations. Often, the fuses may only be checked and replaced by removing the power distribution unit from a rack and opening the power distribution unit. In addition to possibly being time consuming and labor intensive, opening up the unit may violate a warranty on the unit.
Typically, each power distribution unit must be visually inspected in order to determine if a circuit breaking link has opened a circuit. As the number of circuit breaking links increases, it may be more time consuming and difficult to identify the circuit breaking link responsible for the open circuit. Additionally, a remote user may not be aware that a circuit has opened and the electrical devices are no longer receiving power from the power distribution unit.
Despite the inconveniences that may be associated with fuses, many standards setting organizations, certifying bodies, and codes are requiring branched circuit protection. That is, power outlets may be arranged in groups or “branches,” each of which must be separately fused. Branched circuit protection may result in an increased number of fuses in each power distribution unit.